May 1941 scenario -Britain Stands Alone

Neptune also has a massive naval presence, 7 BBs, 5 CA, 17 CL, 135 DD and DE, and over 500 other warships. At this point Germany's entire fleet could match the CL and up numbers the allies brought to bear.
Well as has been pointed out, the objectives of OVERLORD were quite a lot more ambitious than those of SEALION, so a lot more resources had to be thrown at it. The Sealion forces only had to go 40 miles or so to get to London; the Overlord forces had to travel hundreds of miles to get to Berlin. The Overlord forces were much much bigger than the Sealion forces and the opposition to the Sealion forces much weaker - Sealion faced much weaker defences, even the stop lines (including the GHQ line) were only two pill boxes deep. In September 1940 there were only the equivalent of a couple of inexperienced, under-equipped, poorly trained and poorly generaled divisions defending beaches "B" - "E". I would expect a different situation in May 1941 however.

Yes, the British destroyer and destroyer escort force alone had increased by about 60 ships by May 1941 but that didn't stop the period after September 1940 (until March or April 1941) from being part of the first U-boat "happy time". Since there were sufficient ships guarding home waters, most if not all that increase would have gone to the Atlantic or overseas. Even so, there remained a huge disparity in numbers between the Nazi and British navies, and that's what makes it all interesting, seeing if this can somehow be overcome.

Oh, and lets not forget a well played deception based on controlling any information the enemy gets about you, while you are in fact quite well informed about them.

Well the Germans had broken the British naval and meteorological cyphers so they had weather reports from the Atlantic and knew quite a bit about British naval operations. Their knowledge of British land forces was not wholly accurate, but it was an over-estimate so their planning had some cushioning in it. They had pretty good maps of the British fortifications and of Britain in general (including geotechnical maps). The British had good control over their information but didn't know the German intentions exactly, as can be shown by the location of the GHQ reserve - it was placed so it could travel to the east coast if necessary. It's also shown by the announcement of "Cromwell" ("invasion immanent") when no invasion was in the offing.

A longer BoB means more shadow factories can be brought into play, offsetting the lost production of known factories. Also, Germany is losing numbers too, both in pilots and in serviceable aircraft, so a longer Battle only works more in Britain's favour.
That assumes that full production hasn't been reached and a BOB mark 2 will be fought in exactly the same way as Mark 1. If the Germans are successful to begin with, then they will experience a declining loss rate as the battle proceeds and British numbers decline, while British losses increase, so a longer battle will benefit them. Although British numbers have increased and continue to increase, the Germans still have an advantage in the number of experienced pilots.

Before that is was Allied (French, Czech, Polish, etc.) pilots, to such a degree that the British had more active pilots by the time the BoB was over than they'd started with, while the Germans had fewer.
Well they had to struggle to be recognised by the British as something better than monkeys and there aren't any replacements for those pilots from their own countries.

No, Malta wasn't being bombed, and the Italians were held at bay by their own weaknesses.
So you don't know how many there were, either. Some/lots were definitely sent to Malta, Malaya, and Egypt. They had a significant effect on German and Italian forces in North Africa in 1941.
 
Well as has been pointed out, the objectives of OVERLORD were quite a lot more ambitious than those of SEALION, so a lot more resources had to be thrown at it. The Sealion forces only had to go 40 miles or so to get to London; the Overlord forces had to travel hundreds of miles to get to Berlin.
Actually, since the biggest challenge is usually breaking out from the beachheads, the two aren't that different.

The Overlord forces were much much bigger than the Sealion forces and the opposition to the Sealion forces much weaker - Sealion faced much weaker defences, even the stop lines (including the GHQ line) were only two pill boxes deep.
Again, the biggest challenge is breaking out from the beachheads, not advancing across open country, and the Germans plain don't stand a chance. Also the British had a lot more than that, much of it impromptu, which can be a real b*stard to deal with, even if its effect is not strictly as effective as a military-grade defence.

In September 1940 there were only the equivalent of a couple of inexperienced, under-equipped, poorly trained and poorly generaled divisions defending beaches "B" - "E". I would expect a different situation in May 1941 however.
Troops with iron determination, and chemical weapons.

Even so, there remained a huge disparity in numbers between the Nazi and British navies, and that's what makes it all interesting, seeing if this can somehow be overcome.
It can't be, and even if it could, it would still do the Germans no good.

Well the Germans had broken the British naval and meteorological cyphers so they had weather reports from the Atlantic and knew quite a bit about British naval operations.
They knew enough to know that any significant British presence would scupper the plans.

Their knowledge of British land forces was not wholly accurate, but it was an over-estimate so their planning had some cushioning in it.
Not enough.

They had pretty good maps of the British fortifications and of Britain in general (including geotechnical maps).
Except they didn't have enough knowledge, and what they had would have been suspect due to the double-cross system.

That assumes that full production hasn't been reached and a BOB mark 2 will be fought in exactly the same way as Mark 1. If the Germans are successful to begin with, then they will experience a declining loss rate as the battle proceeds and British numbers decline, while British losses increase, so a longer battle will benefit them.
Since this didn't happen OTL, you need to provide some reason for it to happen ATL.

Although British numbers have increased and continue to increase, the Germans still have an advantage in the number of experienced pilots.
The British used their pilots better.

Well they had to struggle to be recognised by the British as something better than monkeys and there aren't any replacements for those pilots from their own countries.
They were respected by the British, and as for replacements, no, they won't be getting any from their own countries, but by the end of the war there were a total of seven Polish fighter squadrons up, plus a night-fighter squadron and two fighter-reconnaissance squadrons, vs two fighter squadrons during the BoB, so even doubling it to four squadrons, there's plenty of reserve there.

So you don't know how many there were, either. Some/lots were definitely sent to Malta, Malaya, and Egypt. They had a significant effect on German and Italian forces in North Africa in 1941.
The Italians were utterly ineffectual, and until the British prove superiority the Germans won't get involved, so the actual needs are minimal.

Basically, you can't win the BoB without gutting the Luftwaffe, and you can't outnavy the RN with the Kriegsmarine, so your chances of an invasion in 1941 are the same as in 1940, EXACTLY O%.
 
Let's not forget, many of the beaches in Britain are silt. Tanks get stuck in silt and have real trouble getting out. Problem is, Germany didn't know this, in fact in 1941 no one really knew this. So a lot of those Panzers are going to get stuck, assuming their transports can even get past the RN and RAF.
Neptune also took place in a condition of WAllied air superiority and almost total naval supremacy. The Germans would be operating under conditions where they have air parity, at best, and the British would have naval superiority. These are not conditions for a successful naval invasion.
This is ultimately where all Sealion plans die. Once the RN sweeps in and drives the Kriegsmarine out of the Channel the invasion is pretty much over. At that point whole divisions will just be starved out.

And even if by some miracle the Kriegsmarine is able to win (which is pretty much ASB) the ports in the area that Germany planned to capture don't have the capacity for enough supplies when they are undamaged, and it is likely that the British will do some damage and lower the capacity still further. Keep in mind that for the Normandy landings the Allies built two artificial harbors to bring in supplies, and even then had problems with supply until they captured Cherbourg.
 
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Oh yeah, that too. The British did a ton of research into what they were facing, a ton of research into how to overcome the difficulties, and put together a ton of intelligence operations to get the Germans looking the wrong way.
 

Saphroneth

Banned
I suppose I should congratulate OP for managing to make a Sealion thread without the word "Sealion" in the title to try and hide it from... well, actual criticism.
It couldn't last.


Anyways.
Important economic question - are the Germans actually paying the Soviets for resources TTL? OTL they invaded Russia shortly before their extension on paying ran out, TTL that is obviously impossible as the Luftwaffe is being ground up over Britain.
 
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